Grinding machine



April 3, 1956 c. G. FLYGARE ET AL GRINDING MACHINE Filed July 15, 1953 4Sheets-Sheet l Z 26 2b 2&3

INVENTORS CA EL 6 F1. YGAEE Emu/pea F W/LDEE BY WWW A T'TORNE Y C. G.FLYGARE ETAL GRINDING MACHINE April 3, 1956 2,740,236

Filed July 15 1953 4 Sheets-Sheet 3 INVENTORS CARL G. FL YGAEE' lg /c/mED A W/LDER Mm-wan.

HTTOENEY April 3, 1956 c. G. FLYGARE ET AL 2,740,236

GRINDING MACHINE Filed July 15, 1955 4 Sheets-Sheet 4 Fig. 6 q /6INVENTORS C'A EL 6. F4 YGAEE 85/ c HA ED F W/LDEI? WA D-sot ATTORNEYUnited States Patent O GRINDING MACHINE iCarl G..Flygare and Richard F.Wilder, Worcester, Mass.,

'assignors to Norton Company,'Worcester, Mass., a corporation ofMassachusetts Application July 15, 1953, Serial No. 368,060

7 Claims. (Cl. 51-92) The invention relates to grinding machines, andmore particularly toan automatically operated surface grinding machine.

a machine for grinding the plane faces on opposite side faces of a pairof integral splines or keys which project diametrically from oppositesides of a work piece.

Another object is to provide an automatically actuated index mechanismfor indexing the work piece 180 after each reciprocation .of the worksupporting table, alternately to present opposite faces of the workpiece for a grinding operation. Another object is to provide anautomatically controlled cycle to stop the grinding operation after apredetermined grinding has takenplace on opposite faces of a work piece.Another object is to provide an electric counter controlled mechanismfor stopping the grinding-operation after apredetermined number ofreciprocations of the work piece relative to the grinding wheel, andthereafter automatically to true the operative face of the grindingwheel. Other objects 'will'be in part obvious or in'part pointed outhereinafter.

One form of the invention has been illustrated in the accompanyingdrawings in which like'referencenumerals indicate like parts:

Fig. 1 is a front elevation of the improved grinding machine;

Fig. 2 is a right hand end elevation of the machine, on an enlargedscale, having parts broken away and shown in section to clarify theillustrations;

Fig. 3 is a fragmentary vertical sectional-view, on an enlarged scale,through the work support, work indexing, and grinding wheel truingmechanism;

.Fig. 4 is a fragmentarysectional view, on an enlarged scale, takenapproximately onthe line 4-4 ofFig. 3, showing the adjustable mechanismfor the truing tool;

Fig. 5 is a left hand end elevation of the parts shown in Fig. 3 showinga portion of the work indexing mechanism; and

Fig. .6 is a combined electrical hydraulic-diagram of the actuatingmechanisms of the machine.

Agrinding machine has been illustrated in the drawings which is of thesurface grinding machine type having a base which supports a verticallymovable wheel slide 11. The wheel slide 11 is supported by a pairofspaced vertically arranged slideways 12 on the base 10, onlyone ofwhich has been illustrated in the drawings. This wheel slide arrangementis substantially the same as that shown in the prior U. S. Patent No.2,080,976to Wallace H. Wood dated May 18, 1937, to which reference maybe had for details ofdisclosure not containedherein.

The wheel slide 11 serves as a. support. for a horizontally arrangedrotatable wheel spindle 13 which is rotatably journalled in bearing(notshown) supported in -a hori- "ice zontally arranged projection 14formed integral with the wheel slide 11. The wheel spindle 13 supports awheel mounting 15 on itsleft hand end which is arranged to support apair of spaced grinding wheels 16 and 17 for simultaneously grindingspaced portions on a work piece.

A suitable driving mechanism is provided for the wheel spindle 13comprising an electric motor 18 mounted on a bracket 19 which isadjustably fastened to the lower end of the wheel slide 11 by aplurality of screws 20. The screws 20 pass through elongated slots (notshown) formed in the bracket 19 and are screw threaded into the wheelslide 11 to facilitate adjusting the position of the bracket 19 and themotor 18 to tension the driving belt. The motor 18 is provided with adriven pulley 21 which is connected by means of a belt 22 with a pulley23 mounted on the right hand end of the wheel spindle 13 (Fig. 2).

A suitable feeding mechanism is provided for imparting a verticalfeeding movement to the slide 11 relative to the base 10. This mechanismmay comprise a rotatable feed screw 25 carried by the wheel slide 11which meshes with a nut '26 fastened to a portion of the base 10. Theupper end of the feed screw 25 is rotatably journalled in ananti-friction bearing 27 carried by the wheel slide 11. The feed screw25 is provided with a bevel gear 28 which meshes with a bevel gear 29mounted on the right hand end of a rotatable shaft 30. The shaft 30 isjournalled in a pair of spaced anti-friction bearings 31 and 32. Amanually operable feed wheel 33 is mounted on the left hand end of theshaft 30. It will be readily apparent from the foregoing disclosure thata rotary motion of the feed wheel 33 will transmit a vertical feedingadjustment to the wheel slide 11. The direction of rotation of the feedwheel 33 will determine the direction of movement of the Wheel slide 11.

The base 10 is provided with a transversely adjustable carriage which isarranged to slide transversely relative to the base 10 on a pair ofspaced flatways 41 and 42 and a centrally located gibbed slideway (notshown) which is identical with that shown in the above mentioned priorpatent. A suitable feeding mechanism provided for imparting a transversemovement to the carriage 40 comprises a rotatable feed screw 43 which isjournalled in spaced anti-friction bearings 44 and 45 carried by thecarriage 40. The feed screw 43 meshes with or engages a half nut 46fixedly mounted on the base 10. A hand wheel 47 is mounted on the lefthand end of the feed screw 43. A rotary motion of the hand wheel 47 willbe transmitted through the screw 43 and the nut 46 to impart atransverse movement to the carriage 40. The direction of rotation of thefeed wheel 47 serves to determine the direction of movement of thecarriage 40 relative to the base 10.

The carriage 40 serves as a support for a longitudinally movable worktable 50 which is slidably supported on a V-way 51 and a flatway 52(Fig. 2) formed on the upper surface of the carriage 40. The table 50may be traversed longitudinally in a conventional manner by means of anold and well known manually operable traversing mechanism comprising arotatable traverse Wheel 55 supported on the outer end of a rotatableshaft 56. The shaft 56 is connected by gearing (not shown) with a rackbar 57 fixedly mounted on the underside of the table 50.

A suitable power operated mechanism may be provided for reciprocatingthe table 50 longitudinally relative to the carriage'40. This mechanismmay comprise a hydraulic cylinder 60 which is preferably fixedlymounted' on the carriage 40. The cylinder 60 contains a slidably mounted(piston 61 having piston rods 62 and 63 projecting from oppositesidesthereof. The outer ends of the piston rods 62 and 63 are connected to apair of spaced depending brackets 64 and 65 depending from the underside of the table 50 and at opposite ends thereof.

A reversing valve 66 is provided for controlling the admission to andexhaust of fluid under pressure from the cylinder 60. The valve 66 isarranged so that it may be actuated either manually or automatically bymeans of a reversing lever 67. A pair of adjustable table dogs 68 and 69(Figs. 1 and 6) are provided to facilitate automatic operation of thereversing valve 67. A combined start-stop and table speed control valve70 which is actuated by a knob 71 is provided for controlling thestopping and starting of the table movement and also for controlling thespeed thereof. These valves are substantially the same as thosedisclosed in the above mentioned prior patent, to which reference may behad for details of disclosure not contained herein.

In order to start reciprocation of the table 50, the knob 71 is pulledoutwardly, that is, downwardly in Fig. 6, to open the V-port to start areciprocating movement of the table 50. The reciprocatory stroke of thetable 50 is governed by the position of the table dogs 63 and 69. Theright hand table dog 69 is positioned so that the table reverses at apoint where the grinding wheels 16 and 17 are directly over a truingapparatus to be hereinafter described. The left hand table dog ispositioned to determine the position of the grinding wheel relative tothe work piece being ground at the other end of the table stroke.

A fluid pressure system is provided for supplying fluid under pressureto the various operating mechanisms of the machine. This system maycomprise a motor driven fluid pump 72 which draws fluid through a pipe73 from a reservoir 74 and forces fluid under pressure through a pipe75. Pressure relief valve 76 is connected to the pipe 75 so that excessfluid under pressure may be exhausted directly to the reservoir 74through a pipe 77 so as to maintain a substantially uniform operatingpressure in the pipe line 75.

The table 50 serves as a support for a work supporting apparatuscomprising a frame 85 which supports a rotatable hollow spindle 86 in apair of spaced anti-friction bearings 87 and 88. The left hand end ofthe hollow spindle is enclosed by a bushing 89 which is screw threadedinto the spindle aperture. The hollow spindle 86 supports alongitudinally movable work spindle 90, the right hand end of which issupported by preloaded ball hearings to facilitate a free axial movementof the work spindle 90. The preloaded ball bearings 91 are supportedwithin an aperture 92 formed within the hollow spindle 86. A compressionspring 93 surrounds a reduced portion of the spindle 90 and isinterposed be tween a shoulder 94 on the spindle 90 and the right handend face of the bushing 39. The compression spring 93 serves normally toexert a pressure toward the right to maintain a frusto-conical nose face95 on the spindle 90 in operative supporting engagement with a hollowend of a work piece 96. A hydraulically operated mechanism is providedfor moving the spindle 90 to the left to facilitate loading andunloading work pieces to be ground. This mechanism may comprise ahydraulic cylinder 97 which contains a slidably mounted piston 93. Thepiston 98 is mounted on the left hand end of the spindle 90. When fluidunder pressure is passed through a pipe 99, through a port 100 into acylinder chamber 101, the piston 93 together with the spindle 90 will bemoved toward the left against the compression of the spring 93 towithdraw the frusto-conical nose portion from engagement with a workpiece 96.

The work piece 96 is a hollow cylindrical-type work piece having twodiametrically opposed splines S and 106 to be ground. As illustrated inFig. 4, the grinding wheels 16 and 17 are positioned simultaneously togrind the upper faces 107 and 108 of the splines 105 and 106respectively when the table 50 is reciprocated longitudinally. Aftergrinding the surfaces 107 and 108, the table 50 returns to the left handend of its stroke, in which position, the work piece 96 is indexedthrough 180 to position the surfaces 109 and 110 of the splines 105 and106 respectively in position for grinding by the grind ing wheels 17 and16 respectively.

A suitable indexing mechanism is provided for indexing the spindle 86automatically in timed relationship with the other operations of themachine. A rotarytype fluid motor is mounted on the upper portion of theframe 85. The motor 115 is provided with a motor shaft 116 having a gear117 keyed thereon. The gear 117 meshes with a gear 118 keyed onto theleft hand end of the spindle 86. An index plate 119 is also keyed ontothe spindle 86 adjacent to the gear 118. The index plate 119 is providedwith diametrically opposite stop surfaces 120 and 121 which are engagedby an index pawl 122 precisely to position the work piece 96 in grindingpositions. The index pawl 122 is formed integral with a piston 123slidably mounted within a cylinder 124. A compression spring 125 servesnormally to maintain the pawl 122 in operative engagement with theperiphery of the index plate 119. When it is desired to impart anindexing movement to the work piece 96, fluid under pressure is passedthrough a pipe 126 into a cylinder chamber 127 to withdraw the indexpawl 122 from engagement with the index plate 119 against thecompression of the spring 125.

A suitable control valve 130 is provided for controlling the admissionto and exhaust of fluid from the cylinder chamber 127. This valve 130 ispreferably a pistontype valve comprising a valve stem 131, the end ofwhich is maintained in operative engagement with the periphery of a cam132. The cam 132 is fastened to the side face of the index plate 119. Acompression spring 133 serves normally to maintain the end of the valvestem 131 in operative engagement with the cam 132. When fluid underpressure is passed through a pipe 134, it passes through the valve 130,through the pipe 126 into the valve chamber 127 to withdraw the indexpawl 122 from operative engagement with the stop surface 120. Fluidunder pressure is continuously passed through a pipe 138, through athrottle valve 139, through a ball check valve and through. a pipe 141to the motor 115 so as to normally exert a pressure tended to rotate themotor shaft together with the index plate 119 and the cam 132 in aclockwise direction (Fig. 6). Fluid under pressure exhausting from themotor 115 exhausts through a pipe 142 and through a relief valve 143into the reservoir 74. By regulating the throttle valve 139, the speedof the motor 115 may be varied as desired.

A control valve 135 is provided for controlling the admission of fluidto the valve 130. The valve 135 is normally held in a left hand endposition by means of a compression spring 136. In the position of thevalve 135 (Fig. 6) fluid under pressure from the pressure line 75 passesthrough a pipe 137 into a valve chamber 144. The valve 135 is providedwith a solenoid S5 which when energized serves to shift the movablevalve member toward the right against the compression of the spring 136so that fluid under pressure entering the valve chamber 144 may passthrough the pipe 134, through the valve 130, through the pipe 126 intothe cylinder chamber 127 to Withdraw the index pawl 122 from engagementwith the surface 120 of the index plate 119. The motor 115 havingpressure thereon immediately starts a rotary mo tion of the index plate119 and the cam 132 in a clockwise direction. During the clockwiserotation of the cam 132, the valve stem 131 rides along a flat surfaceon the cam 132 thereby gradually depressing the valve stem 131 to cutoff the passage or" fluid from the pipe 126 so that fluid within thecylinder chamber 127 may exhaust through the pipe 126, through the valve130 and exhausts through a pipe 145 into the reservoir. The releasedcompression of the spring 125 then moves index pawl 122 into engagementwith the periphery of the index plate 119. The rotary indexing movementconso that'the stop surface 121 engages the pawl 12210 stop the rotaryindexing mo\ ement of the spindle '86 to locate the work piece 96 in anindexed position for grinding the opposite side face of the splines 105and 106 respectively. It will be readily apparent from 'the foregoingdisclosure that each time the solenoid S5 is energized, an indexingmovement will be imparted to the index plate 119 and the work piece. Theenergizing of the solenoid S5 is automatically timed as will behereinafter described.

A power operated downfeeding mechanism is provided for the wheel slide11. The upper end of the feed screw 25 is suspended by a pair of spacedanti-friction bearings 150 and 151 which are in turn supported by anon-rotatable sleeve 152. The periphery ofthe sleeve 152 is screwthreaded and meshes with a surrounding rotatable nut 154. The nut 154 isrotatably journalled in spaced anti-friction bearings 155 and 156. A'gear 157 is fixedly mounted on the periphery of the nut 154 and mesheswith rack teeth 158 formed on a piston 159. The piston 159 is slidablymounted within a cylinder 160. When fluid under pressure is passedthrough a pipe 161 into a cylinder chamber 162 formed at the left handend of the cylinder 160, the piston 159 will be moved toward the right.An adjustable stop screw 163 serves to limit the movement of the piston159 toward the right thereby limiting the power operated downfeed of thegrinding wheels 16 and 17.

A manually operable control valve 164 actuated by a knob 165 is providedfor controlling the admission of fluid under pressure to both thedownfeed cylinder 160 and also to the cylinder chamber 101 forretracting the headstock spindle 90. The control valve 164 is providedwith a valve chamber 166. In the position of the valve 164 (Fig. 6)fluid from the pressure line 75 passes through the valve chamber 166 andthrough a pipe 167 to the cylinder chamber 101 to retract thefrusto-conical nose portion 95 of the spindle'90 to a loading position,that is, toward the left (Fig. 3). During this movement fluid may passfrom the pipe 167 through a ball check valve 171, through a pipe 174into a cylinder chamber 173 to move the piston 159 toward the left.During this movement fluid within vthe cylinder chamber 162 may exhaustthrough the pipe 161, through a valve chamber 169 and out through anexhaust pipe 170 into the reservoir 74.

When it is desired to initiate a downfeeding movement of the wheel slide11, the knob 165 is moved toward the left so that fluid under pressuremay pass through the valve chamber 166, through the pipe 161 into thecylinder chamber 162 to cause the piston 159 .to move toward the rightthereby imparting a rotary motion, through the rack bar 158, to the gear157 to rotate the nut 154 and thereby to impart a downfeeding movementto the grinding wheel slide 11. During this movement fluid may exhaustfrom the cylinder chamber 101, through the pipe 167, through a centralpassage 168 in the valve 164 into the valve chamber 169 and out throughthe exhaust pipe 170. The exhausting of fluid from the cylinder chamber101 serves to release the compression of the spring 93 so that thefrusto-conical nose portion 95 of the spindle 90 moveshinto operativedriving .engagement with the hollow end of the work piece 96.

It is desirable to impart an. incremental rotation to the nut 154 so asto cause a controlled downfeed of the wheel slide 11 at one or both endsof the reciprocatory stroke of the table 50. This is preferablyaccomplished by means of a shuttle-type metering valve 175 whichcontrols the exhausting of fluid from the cylinder chamber 173. Theshuttle valve 175 contains a slidably mounted valve member 176 having avalve chamber 177 formed therein. During a longitudinal shifting .movement of the slidably mounted valve member 176, a predetermined meteringof fluid from the cylinder cham- "ber 173 "is obtained 'to exhaust -'ametered "amount of fluid through an exhaust pipe 178 into the reservoir74.

A control valve 179 is provided for controlling actuation of the shuttlevalve 175. The control valve 179 is normally held in a left hand endposition by a compression spring 180. A solenoid S4 is provided forshifting the control valve 179 into a right hand'endposition, as will behereinafter explained. A pipe 181 conveys fluid from the pressure line75 into a valve chamber 182. In the position of the valve 179 (Fig. 6),fluid entering the valve chamber 182 passes through a pipe 183 throughboth a needle valve 184 and a ball check valve 185, through a pipe 186into an end chamber 187 in the shuttle valve to cause the slidablymounted valve member 176 to move toward the left into aleft hand endposition. As the valve chamber 177 passes across the port at the end ofthe'pipe .174, a predetermined quantity of fluid is metered from orallowed to exhaust from the cylinder chamber 173. During this shiftingmovement of the valve member 176 toward the left (Fig. 6) fluid mayexhaust from an end chamber 188, through a pipe 189, through a throttlevalve 190 into a valve chamber 191, through a central passage 192 withinthe valve 179 into a'valve chamber 193 and out through an exhaust pipe194 into the reservoir 174. The rate of movement of the slidably mountedvalve member 176 may be regulated by manipulation of the throttle valve190 so as to control the quantity" of fluid metered through the valvechamber 177.

When the solenoid S4 is energized, the valve 179 is shifted into a righthand end position so that fluid under pressure entering the valvechamber 182 of the valve 179 passes out through the pipe 189, throughboth the throttle valve 190 and a ball check valve 195 into the endchamber 188 to shift the slidably mounted valve member 176 toward theright. As the chamber 177 passes across the port at the end of the pipe174 a predetermined quantity of fluid will be again metered from thecylinder chamber 173 so as to provide a further incremental downfeed tothe wheel slide 11. 'Duringthe shifting movement of the valve member 176toward the right fluid within the end chamber 187 may exhaust throughthe pipe 186, through the throttle valve 184, through the pipe 183 intothe valve chamber 193 -and out through the exhaust pipe 194 into thereservoir 74. By regulating the throttle valve 184, the rate of movementof the valve member 176 toward the right may be readily controlled so asto regulate the quantity of fluid metered from the cylinder chamber 173.It will be' readily apparent from the foregoing disclosure that bymanipulation of the throttle valves 184 and 190, a different-incrementof feed may be obtained at either stroke of the member 176. The solenoidS4 is'energized in timedrelation with other mechanisms of the machine aswill'be hereinafter described.

The work holding frame 85 also supports a footstock 200 which isadjustably clamped thereon by a plurality of "screws 199 (Fig. 1). Thefootstock 200 supports'a footstock center 201 which is preferably ofthe'old and well known ball bearing type. The footstock center 201supports the right'hand endof a work holder 202 which fits within acentral aperture within'the workpiece 96. The right hand end of the workholder 202 is provided with a frusto-conical face which engages acorrespondingly shaped aperture within the work piece 96. The left handend of the work holder 202 is providedwith a sleeve 203 which isfastened to the work holder 202by means of a pin. .The sleeve203 fitswithin a central aperture 204 formed in the nose portion of the spindle90. The sleeve 203 is provided with atransverselyextending notch 205which is arranged to .mate with .a fiat-workdriver .206 carried withinthe aperture 204 of the. spindle .90. To load a work piece into themachine, thehollow work piece 96 is slid .ontothe workholder 202 afterwhich the work holder 202 and the work piece 96 are placed in positionon the footstock center 201, which is fastened against longitudinalmovement. The spindle 90 is then withdrawn toward the left to move thenose portion 95 toward the left so that the work piece together with thework holder may be swung into axial alignment with the spindle 90 sothat when the spindle 90 is released, the released compression of thespring 93 will move the spindle so that the aperture 204 slides over thesleeve 203 and the driver 206 moves into engagement with the notch 205.

A grinding wheel truing apparatus is provided so that the peripheries ofthe grinding wheels 16 and 17 may be trued periodically either by amanually initiated cycle or automatically after a predetermined numberof grinding operations have been performed. A truing apparatus 210 isadjustably mounted on the right hand end of the work supporting frame85. The truing apparatus 218 includes a vertically arranged plate 211which is provided with a pair of clamping screws 212 and 213 which passthrough clearance holes 214 and 215 respectively. The clearance holesserve to facilitate a vertical adjustment of the plate 211 for settingup the apparatus and repositioning the truing tools when required. Theplate 211 is guided in a vertical direction by a plurality of keys 216,217, 218 and 219 (Fig. 4). In order to facilitate a vertical adjustmentof the plate 211, a slide bar 229 is slidably supported at one end in abearing 221 carried by the frame 85. At the other end, the bar 220 isprovided with a screw-threaded projection 222 which meets with orengages a rotatable nut 223 also carried by the frame 85. The slide bar220 slides within a clearance groove 224 formed in the frame 85. The bar220 projects beyond the vertical plane surface of the frame 85 so that aportion of the bar 220 mates with a slot 224a formed in the verticalplane face of the plate 211. It will be readily apparent from theforegoing disclosure that a rotary motion of the nut 223 serves to causean endwise movement of the bar 22% thereby transmitting a verticaladjustment to the plate 211 so as to raise or lower the truing apparatus210.

A pivotal adjustment is provided for the truing apparatus 210 comprisinga pivot stud 225 which pivotally supports the truing apparatus 216 onthe plate 211. A pair of adjusting screws 226 and 227 (Fig. 4) areprovided to facilitate an angular adjustment of the truing apparatus 210to vary the path of the truing tool as desired. After the truingapparatus has been adjusted, the truing apparatus may be locked to theplate 211 by means of a plurality of clamping screws 228 only one ofwhich has been illustrated in Fig. 3.

A diamond truing tool 236 is mounted on a slide bar 231 which ispreferably supported by a plurality of rollers (Fig. 3) to facilitate atraversing movement of the diamond or truing tool 230 in a directionparallel to the axis of the grinding Wheels 16 and 17. The bar 231 isconnected by a link 232 with left hand end of a piston rod 233 (Fig. 6).The other end of the piston rod 233 is connected to a piston 234slidably mounted within a cylinder 235. The piston and cylinder 235being arranged to impart a reciprocating movement to the slide bar 231for a'truing operation. A control valve 236 is provided for controllingthe admission to and exhaust of fluid from the cylinder 235. The valve236 is normally held in a left hand end position by means of acompression spring 237. A solenoid S2 is provided which when energized,serves to shift the valve 236 into a right hand end position. In theposition shown in Fig. 6 fluid under pressure passing through a pipe 238enters a valve chamber 239 in the valve 236 and passes through a pipe240, through a throttle valve 241 and a ball check valve 242 into acylinder chamber 243 to move the piston 234 toward the left. During thismovement fluid within a cylinder chamber 244 may exhaust through athrottle valve 245, through a pipe 246, into a valve chamber 247,

through a central passage 248 into a valve chamber 249 and out throughan exhaust pipe 250 into the reservoir 74. The throttle valve 245 servesto control the rate of exhaust of fluid from the cylinder chamber 244 soas to control the rate of movement of the piston 234 and the truing tool230 as they are moved toward the left. A ball check valve 251 isprovided so that when the flow of fluid is reversed in the pipe 246fluid under pressure may bypass the throttle valve 245.

When the solenoid S2 is energized and the valve 236 is shifted into aright hand end position fluid under pressure from the pipe 238 passesinto the valve chamber 239 and through the pipe 246, through both thethrottle valve 245 and the ball check valve 251 into the cylinderchamber 244 to cause the piston 234 together with the truing tool 236 tomove toward the right. During this movement fluid within the cylinderchamber 243 is exhausted at a rate controlled by the throttle valve 241into the pipe 240, through the valve chamber 249 and out through theexhaust pipe 250. It will be readily apparent from the foregoingdisclosure that by manipulation of the throttle valves 24-1 and 245, therate of movement of the truing tool may be independently regulatedduring its travel in either direction.

A limit switch LS4 having a pair of normally open and a pair of normallyclosed contacts is arranged to be actuated by and in timed relation withreciprocation of the truing tool carrier rod 231.

It is desirable to provide an automatic downfeeding movement of thegrinding wheel to compensate for truing and wheel wear. The downfeedpreviously described serves to cause an axial down movement of the feedscrew 25 for controlling the infeeding movement of the grinding wheelsinto the Work. The present feeding mechanism is arranged to impart arotary motion to the feed screw automatically to compensate for wheelWear and truing. This mechanism may comprise a ratchet wheel 26% torotate with the manually operable feed wheel 33. A pivotally mounted arm261 (Figs. 2 and 6) carries a pawl 262 which is arranged when moved inone direction to ride idly over the ratchet teeth of the ratchet wheel26th and when moved in the opposite direction to impart a rotary motionto the ratchet wheel 260.

A power operated mechanism is provided for actuating the pawl 262comprising a cylinder 263 containing a slidably mounted piston 264 whichis connected to one end of a piston rod 265. The piston rod 265 isoperatively connected by a stud 266 with the arm 261. A compressionspring 268 serves normally to hold the piston 264 in a right hand endposition. An adjustable stop screw 26) is provided for limiting themovement of the piston 264 toward the right. A stop screw 270 mounted onthe left hand end of the piston rod 265 is arranged to engage andactuate the actuating plunger 271 of the limit switch LS3. When fluidunder pressure is passed through a pipe 272 into a cylinder chamber 273,the piston 264 will be moved toward the left to impart acounterclockwise rotary motion to the ratchet wheel 260 so as to imparta rotary motion to the feed screw 25 thereby providing a compensatingfeed to the grinding wheels 16 and 17.

A controlling valve 275 is provided for controlling the admission to andexhaust of fluid through the pipe 272. The valve 275 is normally held ina left hand end position by means of a compression spring 276. Whenfluid under pressure is passed through a pipe 277 into a valve chamber278 fluid is retained therein. When a solenoid S3 is energized, thevalve 275 is shifted toward the right (Fig.6) so that fluid underpressure entering the valve chamber 278 may pass through the pipe 272into the cylinder chamber 273 to cause a compensating feed. In theposition of the parts as illustrated in Fig. 6, fluid may exhaust fromthe cylinder chamber 273, through the pipe 272 into a valve chamber 279,through a central passage 'valve 285 into a right hand end position. Inthe position illustrated in Fig. 6 fluid under pressure from thepressure line 75 may pass through a pipe 287 into a valve chamber 288and pass through a pipe 238 to both the control valve 236 and thecontrolvalve 275 which serve to control the operation of the grinding wheeltruing mechanism above described. Whenthe solenoid S1 is energized andthe valve 285 is shifted to a right hand'end position, fluid underpressure entering the valve chamber 288 passes through a pipe'289 to thetable reciprocation reversing valve 66 to control the reciprocatorymovement of the longitudinally movabletable 50.

The operation of this improved grinding machine will be readily apparentfromthe foregoing disclosure. After a grinding operation the work table50 stops in a left hand end position, in which position the grindingwheels 16 and 17 are trued in a manner above described. The knob 165 ispushed-in,'that is, toward the right into the position illustrated inFig. 6 so that fluidunder pressure is passed through the pipe 167 intothe cylinder chamber 101 of the cylinder 97'to withdraw the worksupporting and driving spindle 90 toward the left so that the groundwork piece 96 maybe removed from the machine. At

the same time fluid under pressure passing through the pipe 167 passesthrough the ball check valve 171 into the cylinder chamber 173 to movethe piston 159 toward theleft into the position illustrated in Fig. 6 tomove the 'feed screw 25 upwardly to a startingposition.

The pump 72 is started and the knob 71 pulled outwardly so as to renderthe control valve 70 operative. The table 50, however, does notstart'moving since fluid under pressure cannot pass through the'valve285 until thesolenoid S1 is energized. A work piece 96 is mounted on thework holder 202 and then inserted in the machine by placing the righthand end thereof in engagement with the footstock center 201 andswinging the headstock end downwardly so that a flat surface 290'on thework piece 96 rests on the work loading guide 291 and the left hand endof the work piece is supported by a V-shaped guide '292. The V-shapedguide 292 positions the work holder 202 so that when the spindle 90 isreleased the spindle will move into supportingengagement with the sleeve203 and the driver 206 carried by the spindle 90 is released the spindlewill move into supporting engagement with the sleeve 203 and the driver206 carried by "the spindle 90 will move into driving engagement withthe notch 205 formed in the left hand endof the sleeve 203. vIn thisposition of the parts, the knob 165 is moved outwardly, that is, towardthe left (Fig; 6) 'so that'fiuid under pressure may pass through thevalve 164 and through the pipe 161'so that the piston 159 is ready for adownfeeding movement. The piston 59, however, cannot move until thesolenoid S4 is energized as will be hereinafter described. When the knob165 is shifted toward the left fluid under pressure may exhaust from thecylinder chamber 101 thereby releasing the compression of the spring 93to move'the work spindle 90 toward the right into driving and supportingengagement with the work piece 96 and the work holder 202.

A cycle start switch 293 may then be closed to energize the clutch coil294 of an electric counter 295. The counter'295 may be any of the wellknown commercial electric counters, such as for example, the Microflexcounter manufactured by the Signal Electric Company of Moline, Illinois.At the same time'the cycle switch 293 is actuated, a' start switch 296is closed to render the grinding wheel truing mechanism operative sothat the truing opera- "tion of the grinding wheels willfunctionautomatic'ally as controlled by the counter 295. This'cyclestart switch 293 is a momentary contact switch which renders the clutchcoil 294 operative and at the same time energizes the relay CR1 Whichcloses the contactors of the relay switch CR1 to energize the solenoidS1 which shifts the control valve 285 toward the right and at the sametime sets up a holding circuit to hold the clutch coil 294 energizedduring the cycle. The energizing of the solenoid S1 serves to pass fluidthrough the pipe 289 to the table reversing valve 66 to start the table50 moving toward the right. At the end of the table stroke toward theright, the dog 68 shifts the reversing lever'67 in a clockwise directioninto a reverse position thereby shifting the reversing valve 66 andchanging the direction of movement of the table 50. The shifting of thereverse lever closes the normally open limit switch LS1 to energize'arelay switch CR4 and thereby energizing the solenoid S4 "shuttle valvemember 176toward the right ata rate controlled by the throttle valve184. During the movement of the valve member 176 toward the right apredetermined quantity of fluid may exhaust through the pipe 174 therebyreleasing fluid under pressure within the pipe 161 to cause the piston159 to move toward the right by an amount governed by the fluidexhausted from the cylinder chambe: 173 to cause a downward movement ofthe feed screw 25 thereby feeding the grinding wheels 16 and 17downwardly as the table 50 starts to move toward the left. The grindingwheels 16and 17 grind surfaces 107 and 108 as the table moves fromaright hand to a left hand end position. When the table'ap'proaches theleft hand end of its stroke the table dog 69'shifts the reversing lever67 in a counter-clockwise direction and thereby shifts'the reversingvalve to start the table moving from left to right. At the same timecounter-clockwise movement 'of the reversing lever 67 actuates the limitswitch LS2 to energize the relay switch CR5 thereby energizing thesolenoid S5 to shift the valve 135 toward the right so that fluid underpressure is passed through the pipe 134, through the valve 130, throughthe pipe 126 into the cylinder chamber .127 to withdraw the index pawl122 from engagement with the stop surface 120. Fluid under pressure iscontinually supplied through the pipe 141 to the motor so that as soonas the pawl 122 is withdrawn, the index plate 119 together with the workpiece 96 is indexed through 180". Shortly after the indexing movement isstarted, the cam 132'riding on the valve stem 131 shifts the valve'130so that fluid may exhaust from the cylinder chamber 127 therebyreleasing the compression of the spring so that the pawl 122 rides uponthe periphery of the index plate 119 during the remainder of theindexing movement. The indexing continues until the stop-surface 121 onthe index plate 119 rides into engagement with the pawl 122. At the timethe limit switch LS2 is closed, the count coil of the counter 295 isenergized. The table traverses from the left to the right to a thirdreversal. When the reversing lever is shifted in a counterclockwisedirection to initiate a left to right movement of the table, the limitswitch-LS1 is opened to deenergize relay switch CR4 thereby deenergizingthe solenoid S4 to shift the valve 179 into the position illustrated inFig. 6so that fluid underpressure will pass into the chamber 187 toshift the shuttle valve memher 176 toward the left at a rate controlledby the throttle valve 190 thereby allowing a metered exhaust of fluidfrom the cylinder chamber 173 to cause a further downfeed of the feedscrew 25 before the table starts its movement from left to right. Eachtime the table 50 is reversed at the left hand end of its reciprocatorystroke, the indexing mechanism operates to index the work piece 96through so as to alternately'present the faces 107408and 109-110 to thegrinding wheels 16 and 17. "Several passes of the faces 107-408 and109-110 relative to the grinding wheels 16 and 17 are made. The numberof passes being determined by the setting of the counter 295.

The table 50 continues reciprocation in the manner above described withthe grinding wheels being fed downwardly each time the table starts itsmovement from right to left until the electric counter 2% counts outthereby deenergizing relay switch CR1 and the solenoid S1 to cut off theflow of fluid through the pipe 289 to the table reversing valve 66 tostop the table movement at the left hand end of its stroke in a positionfor a grinding wheel truing operation, that is, with the truing tool ordiamond 230 located in a vertical plane directly below the axis of thegrinding wheels 16 and 17. At the time solenoid S1 is deenergized,solenoids S2 and 33 are energized. The deenergized solenoid S1 stopsmovement of the table 50. Energizing solenoid S3 passes fluid underpressure into the cylinder chamber 273 to actuate the pawl 262 to causea compensating feed, that is, rotation of the feed screw 25. Energizingof the solenoid S2 starts a truing cycle causing fluid under pressure topass through the pipe 246 to traverse the piston 234 together with thediamond 23d toward the right (Fig. 6) so as to pass the diamond 230across the peripheral surfaces of the grinding wheels 16 and 17. Whenthe diamond 23% reaches the end of its stroke toward the right (Fig. 6),the normally open contacts of the limit switch LS4 are closed therebyoperating a circuit to deenergize the solenoid S2 so that fluid underpressure passes through the pipe 24% into the cylinder chamber 243 tocause the piston 234 to move toward the left thereby starting a right toleft traverse of the truing tool 230. Before the truin tool 236 startsthe right to left traversing movement, the solenoid S3 is againenergized to again pass fluid through the pipe 272 into the cylinderchamber 273 to again actuate the feed pawl 262 to cause a furthercompensating rotation of the feed screw 25 before the right to lefttraverse of the truing tool 236.

After the faces 107-108 and res-11a of the work piece 96 have beenground to the desired extent, the grinding Wheels 16 and 17 areautomatically trued and the table 50 is stopped in a left hand endposition. The knob 165 of the valve 164 is pushed in so as to pass fluidunder pressure through the pipe 167 into the cylinder chamber 101 tomove the piston 98 together with the spindle 90 toward the left towithdraw the conical nose portion 95 from engagement with the workpiece$6 to facilitate removal of the ground work piece from the machine.Fluid under pressure passing through the pipe 167 also passes throughthe ball check valve 171 through the pipe 174 into the cylinder chamber173 to move the piston 159 toward the left thereby raising the feedscrew 25 together with the wheel slide 11 and the grinding wheels 16 and17 upwardly to their initial positions for the next grinding cycle.

it will thus be seen that there has been provided by this inventionapparatus in which the various objects hereinabovc set forth togetherwith many thoroughly practical advantages are successfully achieved. Asmany embodiments may be made of the above invention and as many changesmight be made in the embodiments above set forth, it is to be understoodthat all matter hereinbefore set forth or shown in the accompanyingdrawings is to be interpreted as illustrative and not in a limitingsense.

We claim:

1.. In a grinding machine having a base, a transversely movable carriagethereon, means to feed said carriage transversely relative to the base,a longitudinally reciprocable table on said carriage, a piston andcylinder on said carriage operatively connected to reciprocate saidtable, a reversing valve therefor, means including a reversing lever anda pair of adjustable table dogs to actuate said valve, a verticallymovable wheel. slide, a horizontally arranged wheel spindle thereon, apair of spaced grinding wheels on said spindle for grinding spaced planesurfaces on a work piece, means including a manually operable feed screwand nut to feed said slide vertically, an inde- 12 pendent hydraulicallyactuated nut and screw mechanism operatively connected to impart anaxial feeding movement to said feed screw incrementally to feed thegrinding wheel toward and from the work at one end of the table stroke,a rotatable work support including an indexable headstock spindle and afootstock to support a work piece to be ground, an electricallycontrolled means actuated by and in timed relation with the tablereciprocation automatically to index said headstock spindle after eachreciprocation of the table at the other end of the table stroke so as toalternately grind spaced faces on opposite sides of a work piece.

2. In a grinding machine as claimed in claim 1, in combination with theparts and features therein specified in which the work index mechanismcomprises a fluid motor operatively connected to impart a continuousrotary thrust to said headstock spindle, an index plate on said spindle,an index pawl slidably supported on said headstock normally to hold saidplate against the thrust of said motor, a spring normally to maintainsaid pawl in engagement with said index plate, a piston and cylinderoperatively connected momentarily to withdraw said pawl to facilitate anindexing movement of said spindle, a valve on said headstock to controlthe admission to and exhaust of fluid from said cylinder, a cam on saidspindle to actuate said valve, and means including a control valveactuated by and in timed relation with the table reciprocation to admitfluid under pressure to said pawl cylinder automatically to index saidspindle after each reciprocation of the table.

3. In a grinding machine as claimed in claim 1, in combination with theparts and features therein specified in which the work index mechanismcomprises a fluid motor operatively connected to impart a rotaryindexing movement to said headstock spindle, means continuously to passfluid under pressure to said motor, an index plate on said spindle, anindex pawl slidably mounted on said headstock normally to hold saidindex plate stationary against the thrust of said motor, yieldable meansnormally to maintain said pawl in engagement with the said index plate,a piston and cylinder operatively connected momentarily to withdraw saidpawl to facilitate an indexing movement of said spindle, a cam on saidheadstock spindle, a normally open piston-type valve on said headstockactuated by said cam and operatively connected to con trol the admissionto and exhaust of fluid from said pawl cylinder, said valve having avalve stem which rides in engagement with said cam, and means includinga control valve actuated by and in timed relation with the tablereversing lever to admit fluid under pressure to said pawl cylinder toindex the headstock spindle after each complete reciprocation of thetable.

4. In a grinding machine as claimed in claim 1, in com bination with theparts and features therein specified of a piston and cylinder to actuatesaid nut and screw mechanism, a shuttle-type metering valve to controlthe exhaust of fluid from said cylinder so as to control the downfeed ofthe grinding wheel, a solenoid-actuated control valve operativelyconnected to actuate said shuttle valve, and means including a limitswitch actuated by said reversing lever to actuate said control valve soas to cause a downfeed of the grinding wheel at table reversal.

5. In a grinding machine as claimed in claim 1, in combination with theparts and features therein specified of a grinding wheel truingapparatus on said table including a reciprocable truing tool, a pistonand cylinder operatively connected to reciprocate said tool, a controlvalve operatively connected to control the admission to and exhaust offluid from opposite ends of said cylinder, a pawl and ratchet mechanismto impart a rotary motion to said feed screw, a piston and cylinderoperatively connected to actuate said pawl, a second control valveoperatively connected to control the admission to and exhaust of fluidfrom said pawl cylinder, a third control valve operatively connected tosaid table reversing valve and to said first and second control valve,said third valve in one position serves to convey fluid under pressureto the table reversing valve and in another position to convey fluidunder pressure to the first and second control valves to control thegrinding wheel truing operation, and means including a limit switchactuated by and in timed relation with the table reciprocation after apredetermined grinding operation to actuate said third control valve soas to initiate a grinding Wheel truing cycle.

6. In a grinding machine as claimed in claim 1, in combination with theparts and features therein specified of a control valve to convey fluidunder pressure to the table reversing valve, an electric counteroperatively connected to actuate said valve, and means including aswitch actuated by and in timed relation with the movement of said tableto impart an impulse to said counter after each reciprocation of thetable, said counter serving at countout to actuate said control valve tostop the table in a loading position after a predetermined number ofcomplete reciprocations.

7. In a grinding machine as claimed in claim 1, in combination with theparts and features therein specified of a control valve to convey fluidunder pressure to the table reversing valve, an electric counteroperatively connected to actuate said valve, means including a switchactuated by the table reversing lever to impart an impulse to saidcounter after each reciprocation of the table, said counter serving atcount-out to actuate said control valve to stop reciprocation of thetable in a truing position after a predetermined number of completereciprocations, and automatically actuated truing apparatus including ahydraulically reciprocated truing tool, a control valve therefor, ahydraulically actuated pawl and ratchet mechanism to rotate said feedscrew to impart a compensating feed to said grinding wheel relative tothe truing tool before each traversing movement thereof, an independentcontrol valve for controlling the truing traverse and for actuating thepicker feed, said counter serving at the count-out to actuate saidlatter control valve to initiate a grinding wheel truing cycle.

References Cited in the file of this patent UNITED STATES PATENTS1,850,799 Junge Mar. 22, 1932 1,925,740 Ward Sept. 5, 1933 1,973,329Bullows Sept. 11, 1934 2,004,426 Booth et al. June 11, 1935 2,080,976Wood May 18, 1937 2,099,674 Bullock et al. Nov. 23, 1937 2,156,970 BurnsMay 2, 1939 2,183,490 Flygare Dec. 12, 1939 2,192,308 Greiner et al.Mar. 5, 1940 2,206,492 Westenberger et al. July 2, 1940 2,292,588Terbrueggen Aug. 11, 1942 2,442,635 Bennett June 1, 1948 2,454,591 Bradyet al. Nov. 23, 1948 2,535,183 Wilson Dec. 26, 1950 2,600,960 Benjaminet al. June 17, 1952 2,639,563 Swainey May 26, 1953

